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<div class="moz-cite-prefix">Le 28/08/2016 22:03, Robert Sherry a
écrit :<br>
</div>
<blockquote
cite="mid:4a491463-618d-a1e4-4570-0d4ea4fcd8e3@comcast.net"
type="cite">
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charset=windows-1252">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(255, 255,
255);">I defined the following two functions:<span
class="Apple-converted-space"> </span></span><br style="color:
rgb(0, 0, 0); font-family: Verdana, Geneva, Helvetica, Arial,
sans-serif; font-size: 13.44px; font-style: normal;
font-variant-ligatures: normal; font-variant-caps: normal;
font-weight: normal; letter-spacing: normal; line-height:
normal; orphans: 2; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<br style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(255, 255,
255);">function [z]=f(x,y)<span class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(255, 255,
255);">z = x + y - 8<span class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(255, 255,
255);">endfunction<span class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<br style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(255, 255,
255);">function [z]=g(x,y)<span class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(255, 255,
255);">z = 2*x + y - 8<span class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(255, 255,
255);">endfunction<span class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<br style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(255, 255,
255);">I then wanted to find the roots of the two functions
(equations). That is, I want a pair of numbers (a,b)<span
class="Apple-converted-space"> </span></span><br style="color:
rgb(0, 0, 0); font-family: Verdana, Geneva, Helvetica, Arial,
sans-serif; font-size: 13.44px; font-style: normal;
font-variant-ligatures: normal; font-variant-caps: normal;
font-weight: normal; letter-spacing: normal; line-height:
normal; orphans: 2; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(255, 255,
255);">such that f(a,b) = g(a,b) = 0. So, I found the function
fsolve in the documentation of Scilab which I believe will do
what I want. So, I ran the following command:<span
class="Apple-converted-space"> </span></span><br style="color:
rgb(0, 0, 0); font-family: Verdana, Geneva, Helvetica, Arial,
sans-serif; font-size: 13.44px; font-style: normal;
font-variant-ligatures: normal; font-variant-caps: normal;
font-weight: normal; letter-spacing: normal; line-height:
normal; orphans: 2; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(255, 255,
255);"> fsolve([0;0],f,g)<span
class="Apple-converted-space"> </span></span><br style="color:
rgb(0, 0, 0); font-family: Verdana, Geneva, Helvetica, Arial,
sans-serif; font-size: 13.44px; font-style: normal;
font-variant-ligatures: normal; font-variant-caps: normal;
font-weight: normal; letter-spacing: normal; line-height:
normal; orphans: 2; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(255, 255,
255);">and it produced the following error:<span
class="Apple-converted-space"> </span></span><br style="color:
rgb(0, 0, 0); font-family: Verdana, Geneva, Helvetica, Arial,
sans-serif; font-size: 13.44px; font-style: normal;
font-variant-ligatures: normal; font-variant-caps: normal;
font-weight: normal; letter-spacing: normal; line-height:
normal; orphans: 2; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(255, 255,
255);"> Undefined variable: y<span
class="Apple-converted-space"> </span></span><br style="color:
rgb(0, 0, 0); font-family: Verdana, Geneva, Helvetica, Arial,
sans-serif; font-size: 13.44px; font-style: normal;
font-variant-ligatures: normal; font-variant-caps: normal;
font-weight: normal; letter-spacing: normal; line-height:
normal; orphans: 2; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(255, 255,
255);"> at line 2 of function f called by : <span
class="Apple-converted-space"> </span></span><br style="color:
rgb(0, 0, 0); font-family: Verdana, Geneva, Helvetica, Arial,
sans-serif; font-size: 13.44px; font-style: normal;
font-variant-ligatures: normal; font-variant-caps: normal;
font-weight: normal; letter-spacing: normal; line-height:
normal; orphans: 2; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(255, 255,
255);"> fsolve([0;0],f,g)<span
class="Apple-converted-space"> </span></span><br style="color:
rgb(0, 0, 0); font-family: Verdana, Geneva, Helvetica, Arial,
sans-serif; font-size: 13.44px; font-style: normal;
font-variant-ligatures: normal; font-variant-caps: normal;
font-weight: normal; letter-spacing: normal; line-height:
normal; orphans: 2; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px; display:
inline !important; float: none; background-color: rgb(255, 255,
255);">I do not understand this error and I am hoping that
somebody can tell me what I am doing wrong.<span
class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
</blockquote>
<br>
You problem is linear. So there are simpler solutions than fsolve()
that is useful for systems of non-linear equations.<br>
Your system is equivalent to the matrix equation<br>
[1 1 ; 2 1]*X = [ 8 ; 8] with X = [x ; y]<br>
Let set<br>
A = [1 1 ; 2 1] ;<br>
// and <br>
b = [ 8 ; 8];<br>
// from A*X = b, we get X with<br>
X = A\b<br>
<tt>--> X = A\b</tt><tt><br>
</tt><tt> X = </tt><tt><br>
</tt><tt> 0.</tt><tt><br>
</tt><tt> 8.</tt><tt><br>
</tt>that means { x=0, y=8 }<br>
<br>
Regards<br>
Samuel<br>
<br>
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